1. Field of the Invention
The present invention relates to hooking and similar apparatus utilized as connections, for example, for cables. More particularly, the present invention relates to the cable connection for supporting, and eventually releasing, equipment such as survival capsules (a form of lifeboat common on oil well platforms at sea).
2. Description of the Prior Art
Numerous hooks have been designed and are used in industry at the present time. These often take the form of large hooks formed of steel, and having a spring-biased second piece which closes the open end of the hook to prevent release of the hook during operation.
Particularly in heavy industry, military and maritime situations, hooks are provided on a piece of equipment in order to make it more mobile, or to allow for it to be transferred from location to location. In these types of circumstances, large cranes and the like are utilized, and the chain or cable of the crane is provided with a large loop or ring which is to be engaged with the piece of equipment to be moved. In this type of circumstance, depending upon the particular use, it may be desirable to have a hook which can be opened either under full load, or without load. This type of hook is in use in industry, in that the industry does provide hooks which are positively locked under full load but, as a result, are not designed to open under no load conditions. In the alternative, the prior art also provides for hooks which will either automatically, or with very simple operation, open when no load is applied, but generally this type of hook is not easy to open in a loaded condition.
One of the common forms of hook available in the industry is the type which, under load, can be opened by use of a long line, chain or other device which actuates a releasing mechanism, and releases the hook when it is under load. In the other form, the action of releasing of the load by placement or by other means automatically releases the hook, and thus terminates the connection between the cable and the device being lifted. The disadvantage of the first form is that external action is required, and that the hooks are not easy to set or release when not under load. The disadvantage of the second form is that it remains locked in emergency situations when it is under load, and thus can present a significant safety risk. Therefore, there is a significant need in the industry to provide an attaching device which can be set to release either automatically at a given lower load limit or can be released under load.
One particular use of this type of equipment is the support of survival capsules or lifeboats aboard ship and on drilling platforms. Survival capsules are essentially enclosed boats that are increasingly being used as replacements for lifeboats on commercial vessels, cruise ships and especially on drilling or other off-shore platforms. Even when stored, survival capsules and lifeboats are commonly supported by a cable on a hoist so that they may be loaded or entered and quickly lowered over the side of a ship or off the side of a platform.
Vessels of this type have particular need for a hook locking mechanism which cannot be released under load (that is, while the vessel is above the water) without substantial inconvenience and the requirement of conscious and deliberate steps to manually release the locking mechanism. This is accomplished by disengaging the coupling to the manual release drive means, typically a hand crank for driving the release mechanism, and stowing it in a location separate from the lock release drive mechanism. Thus it is not readily available to drive the release mechanism without a conscious effort by the operator who must retrieve it from stowage, transfer it to the vicinity of the drive mechanism and mount it in driving relationship thereon, all of which serves to eliminate the possibility that the vessel will be released under conditions when it is not clearly in the water and ready for release from the cable.
Conversely, it is extremely desirable that the same hook be capable of rapidly and simply releasing the lock mechanism, such as after reaching the water, without disturbing the safety protection when under load. Further it is desirable that this operation be entirely controlled by the helmsman enabling him to determine the exact moment of release. Such a device should be automatic after the release of a safety pin or pins that, once removed, permit the automatic disengaging of the hook.